Underwater vehicles, such as torpedoes, are generally of longitudinally elongated configuration and can present storage problems because of the length, particularly if prior to deployment they are stored in the limited confines of e.g. a submarine or even a surface ship. At the same time, it is important to configure such underwater vehicles in a fashion that promotes efficient travel through the water, a design consideration often at odds with longitudinal dimensional considerations for such an underwater vehicle.
In the prior art related to airborne missiles (as opposed to underwater vehicles), there are some examples of arrangements intended to reconfigure or augment the configuration of a missile at or after launch. For example, in U.S. Pat. No. 4,244,294, "Stowable Nozzle Plug and Method for Air Breathing Missile," a missile with an air breathing gas turbine engine is configured with a translating exhaust plug nozzle intended to minimize longitudinal length of the engine section. Specifically, a translatable exhaust nozzle plug is stowed totally within the outer confines of a missile housing and a booster rocket is attached, holding it in place. Upon release of the booster rocket, a spring shifts the translatable portion of the exhaust nozzle plug, such that it extends outside the missile housing. Alternatively, start up of the turbine engine with generation of exhaust gases is referred to as a means for extending the nozzle plug (via the pressure from the exhaust gases) as is a lanyard attached to the booster which ends up being jettisoned, with the lanyard mechanically pulling out or extending the nozzle plug.
In another prior patent related to rocket engines, U.S. Pat. No. 4,525,999, "Actuator for Deploying Flexible Bodies," there is disclosed a rocket motor nozzle extension which is flexible and in a folded position and which has a telescoping actuator assembly attached to it. A gas generator is provided which forces gas into the telescoping actuator which, in turn, extends the telescoping sections which lock in an extended position. The gas in the telescoping sections is vented.